fix: compositor dispatch edge cases, workspace scroll monitor match, tray hot-reload

[dacrab]

Part of the cleanup discussed in #964 — this is the standalone bug-fix slice (each fix independent, no behavior questions beyond what's described).

Workspaces: scroll monitor matching

Message::Scroll located the current workspace with name.contains(w.monitor.as_str()), while the view() filter a few lines below deliberately uses equality — its comment explains .contains() "falsely matches any pair where one name is a substring of the other — most commonly eDP-1 vs DP-1". The scroll handler apparently predated that fix. Consequence: scrolling the laptop (eDP-1) bar matched a DP-1 workspace as current and navigated the external monitor's workspaces. One-line change to ==, mirroring the view filter.

Niri: spawn custom dispatch

CustomDispatch("spawn", args) built Action::Spawn { command: vec![args] } — the whole args string as a single argv element, so spawn kitty --hold sh (or anything with flags) never worked. Split on whitespace like a shell would (no quoting support; happy to switch to shlex if you'd rather).

Hyprland: unescaped interpolation into Lua dispatch

toggle_special("…") / focus special:… / CustomDispatch interpolated user-controlled names straight into the generated Lua string. A special-workspace name containing " or \ (both legal in Hyprland config) produced a Lua syntax error and silently broke toggling on Lua-config systems. Adds a small escape_lua_string helper used at the three interpolation sites.

Tray: config hot-reload silently skipped

Tray was the only module with a config but no ConfigReloaded handling in App::refresh_config, so changing [tray] blocklist / right_click in config.toml did nothing until restart while every sibling hot-reloads. Adds the variant + update arm + wiring, mirroring how notifications/osd do it.